Spark-plug.



s. lB. FUWLBR.

` SPARK PLUG. i APPLICATION FILED APR. 21,1909.

Patented 111111.11910;

ED lsirii'riiis PATENT OFFICE.

SAMUEL lB. EUWLEB, 0I' LAFAYETTE, INDIANA.

erm-PLUG.

caesar. y specificamente man. Patented Mai- 1, 191e.

Application tiled April 21, 1909. Serial No. 491,287.

To all whom it may concern: cerned bein shown in elevation to complete Be it hewn that I, SAMUEL B.

a citizen of the 'Unitedv States, residing at La Fayette, in the county of Tippecanoe, State of Indiana, have invented certain new and useful'lm rovements in Spark-Plugs of which the folliwing is a description, reference being had to the accompanying drawin forming a part hereof. y invention relates to spark plu for igniting the combustible mixture su p ied to an internal combustion engine; an the ob-l ject thereofis to provide a spark plug which will be more reliable, and one less likely to ifail to ignite the charge, than spa-rk plugs at present upon the market. p

Spark plugs for internal combustion engines whenthey fail to ignite the charge generally dh so because of a deposit of carbon or greasewhich is found to have' co1- lected upon the surface of the insulation ex osed to the burning gases within thegcylin er thereby establishin a path along which the purrent of electricity will flow in preference to jumping across the spark gap the resistance of such deposit or coating of carbon being much less than the resistance of the spark gap.

The object of my invention, more specif` ically stated, is to provide a spark plug in which the surface of the insulation exposed to the burning gases will be reduced `to a minimum; and a plug in which a deposit of carbon upon such surface will not accumulate when the plug is in use, Such deosit as occurs being continually removed y the action 'of the current as each successive spark takes pla'ce This action laccording to my understanding of the forcesinvolved is due in part to the action of the current in burning up the carbon and 1n part to themechanical action of the current as the successive sparks occur, although it is not assertedthat other forces may not contribute to the result attained, which, result is a spark plug in which in actual use it has been found that no deposit of carbon accumulates upon the surfac" of the insulation.

In the accompanying'drawing: Figure 1 is .a view showing a vertical central section of my improved spark plug, the upper end thereof with which my invention is not con'- Fowiiua, Ythe view.

surroundin ig. 2 is a view showing my as seen from a point beneath it.

spark tplug y In e drawing 1 is a bushing designed ing to be secured in the wall of the' wor cylinder of an internal combustion engine Ato which end it is shown threaded as at 2,

and with a hexagonal portion at .3; This bushing it will be understood forms one of .the electrodes of my improved spark plug,

and itis provided with a assage extending longitudinally thereof and withinwhich is locatedl a cylinder 4 of insulating material, the insulating material being secured in place by a cap 5 which engages a threaded portion of thebushin y1, suitable packing washers 6 bein emp oyed as is usual in spark plugs. he bushing 1 projects into t e working cylinder of the engine with which the spark plug is used and the insulating material L and bushinv 1 terminate in the same plane in the embodiment of my invention illustrated and as shown in Fi 1 where `the end 7 of the bushing 1 wil be seen to be in the same lane as the end 8 of thel insulating cylin er 4. 9 is the second electrode ofm im roveds ark plug,

and a disk 10 is pre' crab y provi ed at the -inner end Aof said electrode whichudisk is incontact lwith the end of the insulating cylinder 4.

In my improved electricity in passing between the electrodes 1 and 9 will traverse the ath of least resistance, which path,'when t e lug is used under `the conditions norma y occurring in internal combustion engines will be across the surface ofthe end 8 of the insulating cylinder 4, the length of such ath being a minimum and the material t ereof being commonly a better conductor than the ases the end of the electrode.` analysis wil not, of course, exclude a condition if such 'a condition may exist, in which the current flows through the gases but close to the surface referred to, the essential consideration being that the flow of current Vtakes place alon the same path in which a deposit of car njtends to accumulate. .This continual flow of current over and close to lif not upon the surface upon which a deposit of carbon tends to accumuspark plug va current of` late will prevent the formation of a deposit of carbon upon such surface according to my experience, my theory being that. the results observed are due to'thefact that the carbon is in part burned up by the current as fast as it forms and 1n part dissipated or torn oli' and thrown away from such surface by the well known mechanical action 'observed when a current of electricity of high tension flows along a path upon 'which loose particles lie.

While I have illustrated my invention as embodied in a spark plug having concentric electrodes and one in which the iiow of current is expected to take place along a straight line lying in a sider 'my inventionas plug necessarily having such structural fea'- tures;v and I consider my invention as comprehending spark plugs1in which the path along which the current is designed to flow .lies-in lor substantially in the surface of the insulatin material exposed to the burning gases an u on which a deposit of carbon will accumu ate if such a de osit occurs, or, as stated diierently, s ar plugs in which the surface of the insu ating material exposed to the burning gases embraces or substantially embraces the path traversed by the current as a spark is produced.

Havin thus described my'invention and explaiiie the mode of operation. thereof, I claim and desire to secure by Letters Pat- 'entz- 1. a spark plug for internal combus tion engines an outer electrode consisting of a hollow body portion terminating in' an annular surface, an inner electrode extending through the hollow body portion of the outer electrode and terminating in substantially'ithe plane of the annular surface of the outer electrode, insulating material fillin the space between the two electrodes an terminating in substantially the ,plane of said annular surface, said inner electrode having'its end of greater diameter than its body 'portion'whereby a spark gap is secured of less length than the' thickness of the insulatin materialY between the body portions of e two electrodes.

2. In a spark plug for internal combustion enines an outer electrode consisting of a ho ow body portion terminating-in an annularv surface, aninner electrode extending through the hollowbody portion of the outer electrode and4 terminating in substantially the plane of the annular-surface of the outer electrodeinsulating material filling the space between the tw`o electrodes and terminatiiig in substantially the plane of said annular surface, said inner electrode having at its end anfannular enlarged portion concentric with the annular surface at the end plane, I do not con imited to a spark tion engines yan outer electrode consisting ofA a liollowbody portion-terminating in an annular surface,an inner electrode extending through the hollow body portion of the outer electrode and terminating in substantially the plane of the annular surface of the outer electrode, insulating material filling the space between the two electrodesv and terminating in substantially the plane of said annular surface, saidi'nner electrode having at its end a disk concentric with the annular surface at the end of the outer electrode and in contact with the end of the insulating material.

4. 1n a spark plug for internal combustion engines, a bushing adapted to be secured in the wallv of the working cylinder of an engine and which bushing forms one electrode; a second electrode located within said 'bushing and arranged concentric therewith; and a body of insulating material filling the space between said bushing and said 'second electrode, said inner. electrode having an enlarged portion at its extremity in contactwith theinner end of said body of insulating material, tlie surface of said insulating material exposed to the gases witli-k in the cylinder, the inner end of said bushing, and the end of said second electrode being substantially in one plane whereby the path traversed by a current of electricity as a -spark is produced between the electrodes will extend acros's the surface of said insulating material exposed to the Aburning gases.

5. In a spark plug for internal combustion engines, a bushing adapted to be secured in the wall of the working cylinder of an engine and which bushing forms one electrode; a second electrode located within said bushing; and a body of insulating material s urrounding said second electrode and filling the s ace between said electrodes, said inner e ectrode having an enlarged portion at its extremity in contact with thel inner end of said body of insulating material, the arrangement of said insulating material relatively to said electrodes being such that the l path followed by a current of electricity l950,847 v ,B

outer electrode and parallel therewith, inannular surface on the end of the outer 10 suiating materialfllmg the space `between electrode. i A

the tw electrodes and terminating in a fiat f This specification signed and witnessed surac'e in tlhe sanefpane Withlthe alnula 1 this fteenth day of April A. D. 1909.

sur ace et tie en Yo t e outer e ectro e, an g' a Het, disk on the end of the inner electrode l SAMUEL FOWLER in cpntact with the end of the insulating In 'thel presence ofmaterial, of greater diameter than the in- 1 PERRY F. WRIGHT, ner electrode arranged cncentriewith'thei' G. W. ILGENFRITZ. 

